Ram air fan and power electronics cooling systems

ABSTRACT

A power electronics cooling system includes a ram air fan with one or more blades and a ram air fan motor connected via an output shaft. The ram air fan draws in air and passes it across a heat exchanger to cool one or more cooling liquids. One or more pumps pressurize and pump the cooling liquids to various electronic components, including one or more motor controllers. The pumps may be mechanically or electrically coupled to the output shaft of the ram air fan, such that the motor of the ram air fan provides energy to the pumps.

CROSS REFERENCE TO RELATED APPLICATION

This application is a divisional of, claims priority to and the benefitof, U.S. patent application Ser. No. 15/797,616 FILED ON Oct. 30, 2017and entitled “RAM AIR FAN AND POWER ELECTRONICS COOLING SYSTEMS,” whichis a divisional of, and claims priority to and the benefit of, U.S.patent application Ser. No. 14/457,242 filed on Aug. 12, 2014 andentitled “RAM AIR FAN AND POWER ELECTRONICS COOLING SYSTEMS”, both ofwhich are hereby incorporated by reference in their entirety.

FIELD

The present disclosure relates generally to power electronics coolingsystems in aircraft and more specifically, to the use of ram air fans topower such cooling systems.

BACKGROUND

Conventionally, various types of aircraft utilize ram air flow forcooling various components of the aircraft, such as lubrication and/orelectrical components. Air drawn from the outside environment by a ramair fan may be passed across a heat exchanger to provide cooling tovarious cooling liquids. Typically, pumps are used to circulate coolingliquid and deliver it to components that would benefit from cooling.These pumps may be located at positions remote from the ram air fan,including, for example, in one or more wheel wells.

SUMMARY

A power electronics cooling system in accordance with the presentdisclosure may comprise a ram air fan comprising an air inlet and ablade mechanically coupled to an output shaft, a first pump motorcoupled to a first cooling pump, wherein the first pump motor ismechanically coupled to the output shaft of the ram air fan, wherein thefirst cooling pump pumps a first cooling liquid through a heatexchanger, and wherein the blade forces air through the heat exchanger.The first cooling liquid may be pumped through the heat exchanger and toa first electronics package. The first electronics package may comprisea first ram fan motor controller. Further, a second electronics packagemay comprise a second motor controller. A second motor may be coupled toa second cooling pump, wherein the second cooling pump pumps a secondcooling liquid through the heat exchanger and to the second electronicspackage. The ram air fan and first pump motor may be located on anaircraft, wherein the first pump motor comprises a first shaft and firstgear configured to engage with and transfer rotation from an output gearof the output shaft, and the output shaft of the ram air fan providesrotation to the first pump motor while the aircraft is in flight. Thefirst pump motor may comprise a first clutch configured to prevent thefirst pump motor from rotating faster than a predetermined speed. Thefirst motor controller may provide electrical energy to the ram air fanwhile the aircraft is on the ground.

Another power electronics cooling system in accordance with the presentdisclosure may include a ram air fan comprising an air inlet and a blademechanically coupled to a motor, a first pump motor coupled to a firstcooling pump, wherein the first pump motor is electrically coupled tothe motor of the ram air fan, wherein the first cooling pump pumps afirst cooling liquid through a heat exchanger, and wherein the bladeforces air through the heat exchanger. The first cooling liquid may bepumped through the heat exchanger and to a first electronics package.The first electronics package may comprise a first ram fan motorcontroller. Further, a second electronics package may comprise a secondmotor controller. A second motor may be coupled to a second coolingpump, wherein the second cooling pump pumps a second cooling liquidthrough the heat exchanger and to the second electronics package. Theram air fan and first pump motor may be located on an aircraft and themotor of the ram air fan provides electrical energy to the first pumpmotor while the aircraft is in flight. The first motor controller mayprovide electrical energy to the ram air fan while the aircraft is onthe ground.

BRIEF DESCRIPTION OF THE DRAWINGS

The subject matter of the present disclosure is particularly pointed outand distinctly claimed in the concluding portion of the specification. Amore complete understanding of the present disclosure, however, may bestbe obtained by referring to the detailed description and claims whenconsidered in connection with the drawing figures, wherein like numeralsdenote like elements.

FIG. 1 illustrates, in accordance with various embodiments, a schematicof a power electronics cooling system;

FIG. 2 illustrates, in accordance with various embodiments, a schematicof a ram air fan and power electronics cooling system; and

FIG. 3 illustrates, in accordance with various embodiments, a schematicof a further ram air fan and power electronics cooling system; and

FIG. 4 illustrates, in accordance with various embodiments, across-sectional view of a ram air fan and power electronics coolingsystem.

DETAILED DESCRIPTION

The detailed description of exemplary embodiments herein makes referenceto the accompanying drawings, which show exemplary embodiments by way ofillustration and their best mode. While these exemplary embodiments aredescribed in sufficient detail to enable those skilled in the art topractice the inventions, it should be understood that other embodimentsmay be realized and that logical and mechanical changes may be madewithout departing from the spirit and scope of the inventions. Thus, thedetailed description herein is presented for purposes of illustrationonly and not for limitation. For example, any reference to singularincludes plural embodiments, and any reference to more than onecomponent or step may include a singular embodiment or step. Also, anyreference to attached, fixed, connected or the like may includepermanent, removable, temporary, partial, full and/or any other possibleattachment option.

As used herein, “aft” refers to the direction associated with the tailof an aircraft, or generally, to the direction of exhaust of the gasturbine. As used herein, “fore” refers to the direction associated withthe nose of an aircraft, or generally, to the direction of flight ormotion.

Power electronics cooling systems in accordance with the presentdisclosure may comprise a ram air fan capable of providing cooling airto a heat exchanger. One or more cooling liquids may be pumped throughthe heat exchanger to provide cooling to one or more electronicscomponents. For example, a first and/or second motor controller may becooled by such cooling liquids.

Accordingly, with reference to FIG. 1, a schematic view of a coolingsystem 100 is illustrated. In various embodiments, cooling system 100comprises a ram air fan 102. In various embodiments, ram air fan 102draws in air from outside of the aircraft and passes it across a heatexchanger 112 to provide cooling to components of an aircraft, such asvarious electronic components.

In various embodiments, cooling system 100 further comprises a firstcooling pump 104. For example, first cooling pump 104 is configured topump a first cooling liquid 108 to other components of the coolingsystem. In various embodiments, first cooling pump 104 pumps firstcooling liquid 108 to a first electronics package 106. For example,first cooling liquid 108 may cool a first electronics package 106 duringoperation of the aircraft to avoid overheating and damage occurring tocomponents of first electronics package 106.

Cooling system 100 may further comprise, for example, a second coolingpump 114 configured to pump a second cooling liquid 118 to othercomponents of the cooling system. For example, second cooling pump 114may cool a second electronics package 116 during operation of theaircraft to prevent overheating and damage occurring to components ofsecond electronics package 116.

In various embodiments, heat exchanger 112 may comprise, for example, across-flow type exchanger configured to use air from the environment tocool one or more liquid streams. For example, in various embodiments,first cooling liquid 108 is passed through and cooled by heat exchanger112. In such embodiments, air drawn from the outside environment by ramair fan 102 may be pumped across heat exchanger 112, providing coolingto first cooling liquid 108.

With reference to FIG. 2, ram air fan 102 may be electrically coupled tofirst electronics package 106. For example, first electronics packagemay comprise a first motor controller 136. In various embodiments, firstmotor controller 136 may be capable of providing electrical power to andcontrolling an electric motor. First electronics package 106 may furthercomprise multiple motor controllers, including controllers configured toperform cabin air compression, provide main and auxiliary engine starts,control hydraulic pump motors, control fuel pump motors, and otherfunctions. Any number and type of motor controller is within the scopeof the present disclosure.

In various embodiments, ram air fan 102 comprises a ram air fan motor130. For example, ram air fan motor 130 may comprise a three-phaseelectrical motor. When the aircraft is on the ground (such as taxiing,for example), three-phase AC electrical energy may be supplied to ramair fan motor 130 by, for example, first motor controller 136, causingair to be drawn in through air inlet 110. When the aircraft is inflight, ram air fan motor 130 may be rotated by airflow throughwindmilling, generating electrical energy. In various embodiments,electrical energy generated by ram air fan motor 130 may be used topower components of cooling system 100.

Cooling system 100 may also comprise, for example, a first pump motor134. In various embodiments, first pump motor 134 may be coupled tofirst cooling pump 104 such that rotation of first pump motor 134 causesfirst cooling pump 104 to pressurize and pump first cooling liquid 108.Similarly, cooling system 100 may further comprise a second pump motor144.

With reference to FIG. 3, ram air fan 102 may, for example, bemechanically coupled to first cooling pump 104. In such embodiments,while the aircraft is in flight, ram air fan 102 may be rotated byairflow, often referred to as “windmilling,” which in turn may causefirst cooling pump 104 to pressurize and pump first cooling liquid 108.In various embodiments, when the aircraft is not in flight, power may beapplied to an electric motor within ram air fan 102, which in turncauses first cooling pump 104 to pressurize and pump first coolingliquid 108.

With reference to FIG. 4, a ram air fan 102 may be mechanically coupledto both first cooling pump 104 and second cooling pump 114. In suchconfigurations, rotation of ram air fan 102 is mechanically translatedto pumping in both first cooling pump 104 and second cooling pump 114.

In various embodiments, ram air fan 102 comprises one or more blades 140located in or near air inlet 110. As blades 140 are rotated, air isdrawn in through air inlet 110 and through ram air fan 102. In variousembodiments, blades 140 are mechanically coupled to ram air fan motor130 via an output shaft 120. Rotation of blades 140 may cause outputshaft 120 and ram air fan motor 130 to rotate and vice versa. Forexample, electrical energy may be applied to ram air fan motor 130 whichcauses output shaft 120 and blades 140 to rotate. In other situations,such as during flight, airflow may cause blades 140 to rotate outputshaft 120 and ram air fan motor 130.

In various embodiments, output shaft 120 may be mechanically coupled toa gear 122. For example, gear 122 may be permanently coupled to outputshaft 120 such as, for example, by welding. In further embodiments, gear122 may be removably coupled to output shaft 120 such as, for example,by press fit, threading, or a keyed fit. Any manner of coupling outputshaft 120 and gear 122 is within the scope of the present disclosure.

Cooling system 100 may further comprise a first cooling pump gear 124 aconfigured to engage with gear 122. For example, as output shaft 120rotates, gear 122 transfers rotation to first cooling pump gear 124 a.In various embodiments, first cooling pump gear 124 a may bemechanically coupled to a first cooling pump shaft 126 a. First coolingpump shaft 126 a may be configured to transfer rotation of output shaft120 to a first cooling pump 104.

In various embodiments, first cooling pump shaft 126 a also comprises afirst clutch 132 a. First clutch 132 a may prevent first cooling pump104 from rotating at a speed above a predetermined speed. For example,while the aircraft is in flight, blades 140 may cause output shaft 120to rotate at a higher speed than a predetermined speed, causing firstcooling pump 104 to rotate at a higher rate of speed than thepredetermined speed. In such conditions, first clutch 132 a may limitthe rotation of first cooling pump 104 to at or below the predeterminedspeed.

Cooling system 100 may further comprise, for example, a second coolingpump gear 124 b and a second cooling pump shaft 126 b. Similarly tofirst cooling pump gear 124 a and first cooling pump shaft 126 a, secondcooling pump gear 124 b and second cooling pump shaft 126 b aremechanically coupled and configured to transfer rotation from outputshaft 120 to a second cooling pump 114.

In various embodiments, second cooling pump shaft 126 b also comprises asecond clutch 132 b. Similarly to first clutch 132 a, second clutch 132b may prevent second cooling pump 114 from rotating at a speed above apredetermined speed.

Benefits, other advantages, and solutions to problems have beendescribed herein with regard to specific embodiments. Furthermore, theconnecting lines shown in the various figures contained herein areintended to represent exemplary functional relationships and/or physicalcouplings between the various elements. It should be noted that manyalternative or additional functional relationships or physicalconnections may be present in a practical system. However, the benefits,advantages, solutions to problems, and any elements that may cause anybenefit, advantage, or solution to occur or become more pronounced arenot to be construed as critical, required, or essential features orelements of the inventions. The scope of the inventions is accordinglyto be limited by nothing other than the appended claims, in whichreference to an element in the singular is not intended to mean “one andonly one” unless explicitly so stated, but rather “one or more.”Moreover, where a phrase similar to “at least one of A, B, or C” is usedin the claims, it is intended that the phrase be interpreted to meanthat A alone may be present in an embodiment, B alone may be present inan embodiment, C alone may be present in an embodiment, or that anycombination of the elements A, B and C may be present in a singleembodiment; for example, A and B, A and C, B and C, or A and B and C.Different cross-hatching is used throughout the figures to denotedifferent parts but not necessarily to denote the same or differentmaterials.

Systems, methods and apparatus are provided herein. In the detaileddescription herein, references to “one embodiment,” “an embodiment,” “anexample embodiment,” etc., indicate that the embodiment described mayinclude a particular feature, structure, or characteristic, but everyembodiment may not necessarily include the particular feature,structure, or characteristic. Moreover, such phrases are not necessarilyreferring to the same embodiment. Further, when a particular feature,structure, or characteristic is described in connection with anembodiment, it is submitted that it is within the knowledge of oneskilled in the art to affect such feature, structure, or characteristicin connection with other embodiments whether or not explicitlydescribed. After reading the description, it will be apparent to oneskilled in the relevant art(s) how to implement the disclosure inalternative embodiments.

Furthermore, no element, component, or method step in the presentdisclosure is intended to be dedicated to the public regardless ofwhether the element, component, or method step is explicitly recited inthe claims. No claim element herein is to be construed under theprovisions of 35 U.S.C. 112(f), unless the element is expressly recitedusing the phrase “means for.” As used herein, the terms “comprises,”“comprising,” or any other variation thereof, are intended to cover anon-exclusive inclusion, such that a process, method, article, orapparatus that comprises a list of elements does not include only thoseelements but may include other elements not expressly listed or inherentto such process, method, article, or apparatus.

What is claimed is:
 1. A power electronics cooling system comprising: aram air fan comprising an air inlet and a blade mechanically coupled toan output shaft; a first pump motor coupled to a first cooling pump,wherein the first pump motor is mechanically coupled to the output shaftof the ram air fan, wherein the first cooling pump pumps a first coolingliquid through a heat exchanger, and wherein the blade forces airthrough the heat exchanger, wherein the first cooling liquid is pumpedthrough the heat exchanger and to a first electronics package, andwherein the first electronics package comprises a first motorcontroller.
 2. The power electronics cooling system of claim 1, whereinthe first pump motor comprises a first clutch configured to prevent thefirst pump motor from rotating faster than a predetermined speed.